In a conventional art, an outer plate or the like, applied to a fuselage of a civil aircraft employs an aluminum alloy plate to reduce the weight thereof, and, in order to further reduce the weight, processing of partially thinning a plate member, i.e., wall thinning, is performed. Then, the outer plate forming a fuselage shape of an aircraft is molded to have a curved shape with a certain radius of curvature, and in general, wall thinning is performed by chemical milling after press bending of the flat plate. In addition, as the other molding methods, for example, methods disclosed in the following Patent Documents 1 and 2 are provided.
Patent Document 1 discloses a method of performing wall thinning by machining after an outer plate is molded at a flat plate state.
Patent Document 2 has proposed a molding method for a plate-shaped workpiece, in which a shot material is projected to the plate-shaped workpiece to provide a predetermined radius of curvature, the method including a pre-process of adjusting a plate thickness of the plate-shaped workpiece, before performing the molding to provide a predetermined radius of curvature, such that the plate-shaped workpiece can function as a product after the molding, and a process of projecting the shot material to the plate-shaped workpiece passed through the pre-process to provide the predetermined radius of curvature.